The thermal runaway hazards pose a serious threat to the application and transport of lithium-ion batteries on the aircraft. Hence, the researches of thermal safety in flight condition are necessary. In this study, the tests were conducted in a dynamic pressure chamber to study the effects of ambient pressure and heating power on the thermal runaway characteristics. The results show that the fierce behaviors of jet fire, deflagration, and explosion only were observed in high ambient pressure with high heating power. The open time of the safety valve is advanced as pressure from 95 kPa to 20 kPa. The parameters of heat release rate (HRR), total heat release (THR), cell surface temperature, peak concentration of CO₂, and mass loss decrease as the descend of external pressure or heating power. The peak values of hydrocarbon (CH_x) and CO increase with the descent of pressure but decrease as the reduction of heating power. The effects of ambient pressure on the thermal runaway (TR) fire behaviors mainly attribute to the low oxygen density. The time of heating and smoking may account for the difference of TR behaviors with various heating power. It is revealed that the fire risk and the hazards of toxic/flammable gas emissions are tightly relative to the TR behaviors. These results provide valuable proposals and inspiration for the safety warning and hazard reduction under low pressure.

With the development and application of electric vehicles powered by lithium-ion batteries (LIBs) at high altitude, the lack of research on the aging laws and mechanisms of LIBs under a low-pressure aviation environment has become an important obstacle to their safe application. Herein, the influences and mechanisms of high-altitude and low-pressure environment (50 kPa) on the cycling performance of commercial pouch LIBs were systematically studied. The results showed that low air pressure caused a sharp decrease in battery capacity to 46.6% after 200 cycles, with a significant increase in charge transfer impedance by 70%, and the contribution rate of active lithium loss reached 74%. Low air pressure led to irreversible deformation of the battery, resulting in the expansion of the gap between the electrodes, poor electrolyte infiltration, and reduction of the effective lithium insertion area, which in turn induced multiple synergistic accelerated decay mechanisms, including obstructed lithium-ion transmission, reduced interfacial reaction efficiency, increased active lithium consumption, changes in heat generation structure, and a significant increase in heat generation. After applying external force, the deformation of the electrode was effectively suppressed, and the cycle capacity retention rate increased to 87.6%, which significantly alleviated the performance degradation of LIBs in low pressure environment. This work provides a key theoretical basis and engineering solutions for the design of power batteries in high-altitude areas.

Coastal cities exposed to extreme wind events are facing increasing challenges in emergency management under climate change. Accurate and high-resolution wind environment information over complex urban terrain is essential for disaster risk assessment and evidence-based emergency planning; however, such information is often unavailable in conventional management practices. This study proposes an integrated UAV–CFD framework to support urban wind risk assessment by combining multi-source geospatial data and high-resolution numerical simulation. A refined urban terrain model with a spatial resolution of 0.5 m was constructed through the fusion of Google Earth data and UAV oblique photogrammetry, and subsequently coupled with a computational fluid dynamics (CFD) model to analyze the urban wind environment. Field measurements obtained from a 50 m wind observation tower were used to validate the simulation results. The results reveal significant wind speed amplification caused by complex terrain and building configurations, with a maximum amplification factor of 1.95 due to the canyon effect. The relative errors between simulated and measured wind speeds and turbulence intensity were generally within 15%, demonstrating the reliability of the proposed framework. By providing high-resolution and spatially explicit wind risk information, this study offers practical decision-support for emergency management, urban planning, and resilience-oriented disaster mitigation in coastal cities.